Pneumatic tire.



T. DUNN, PNEUMATIC TIRE;

APPLICATION FILED NOV. 25, 1910.

Patented July 11,1911,

UNTTE STATES PATENT orrion.

THOMAS DUNN, OF LONDON, ENGLAND.

PNEUMATIC TIRE.

Specification of Letters Patent.

Patented July 11, 1911.

Application filed November 25, 1910. Serial No. 594.133.

To'a ll whom it may concern:

Be it'known that I, THOMAS DUNN, rc-

' siding at 56 Moorgate street, in the city of London, England, have invented certain new and useful Improvements in Pneumatic Tires; and I do hereby declare'the followingto be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it'appertains to make and use-the same.

This invention'has for its object an improved method of reinforcing theair tubes of pneumatic tires, so that, by so supporting the fabric of the cover, and distributing the strains to which it is subject in use, thatits liability to'failurewill be greatly reduced and its life greatly prolonged, all the chief causes of tire tronblemayi'be avoided, and that covers too worn or damaged to admit otherwise of further use may be made'to yield toa new lease of life, probably longer even than their first when used with ordinary unsupported tubesj When an ordinary tube is inflated with an ordinary outer cover, it is considerably distended both laterally and circumferentially, and that portion which lies between the toes of the beads is stretched tova far greater extent than the rest of the tube which abut-s closely against the inside of the outer cover, indeed to an excessive degree, andthere is always the danger of this base portion of the tube 'perishing through this ex cessive distention after the tube has been in use for some time. N9w, according-to the present invention, means are arranged whereby. in particular, any excessive distention of-the inner tube is prevented, and it is relieved of this unequal strain, whereby the life of the tube is prolonged, while' the construction also provides for absolute security in keeping the heels of the beads within the channel of the rim even after deflation.

The drawing shows a cross section through a pneumatic tire constructed ac-' cording to this invention. i

In the drawings a 1s the outer cover, and Z) is an ordinary innertube. The tube is unjoined and drawn into an inextensible' pocket 0. One means of'making this pocket 0 is to wind a linen or other textile thread upon a collapsible mandrel that is first covered with a thin rubber proofed Holland or similar suitable fabric, the threads being previousy repeatedly passed through rub: bei; solution so thatthey will adhere securely of the space within the the one to the other and to the interior skin of the fabric. The pocket thus made is then I stripped from the mandrel and the unjoined tube is drawn through it and its ends re- JOII] 9(l. Thetube is then slightly inflated and around the tread portion of the pocket portion having the same effect, the thread or its equivalent and the exposed surface of the pockets being finally wrapped and vulcanized in the usual way. The tube so covered will only occupy in order to insure the whole of such space bein'gfilled, a secondary inner tube (Z is provided, whlch tube is also provided with an inextensiblc ocket e, which pocket has a circumferentlally wound inextensible band 9 upon its outer portion, this portion being rubber solutioned to the inner circumference of the larger tube pocket '0. This smaller or secondary tube prevents the heels of the cover beads froindisengaging themselves from the'channels of the rim even should the larger tube deflate; and, to obviate' this trouble arisin should the smaller secondary tube by any chance deflate, the

outer covering of the secondary tube a is made of a double thickness at its base and is adapted to in'close a sectional steel band 72.-

A communication for inflation may bemade between the two air tubes in which case a single valve will suffice for both. On the other hand. the secondary tube may about three quarters outer cover, and,

be, and preferably is, made butt ended, the J larger tube and the smaller tube being in this caseeach provided with a valve for inflation.- If this latter method is adopted the valves may be placed diametrically opposite one another, the 'valve of the larger tube being placed between the butted ends of the smaller tube. Sinceneither tubes are extensible laterally or only very slightly so, the larger tube, if not supported by the secondary tube would take up the position as shown in dotted lines at j,- but, when the smaller'secondary air tube is provided and inflated, it forces the inner side'of the larger tube upward the meeting surfaces of the two tubes forming a diaphragm across the section of the' 'tire, and the air pressure by forcing'tiwbase of tliejlsec ondary tube down into the channel at the base of the outer cover between the beads automatically setsthe two tubes with the inextensiole band in the tread in their correct position within :the cover.

The steel band it assists the tube as whole automatically to find its exactly correct position within the cover. The band need not necessarily be made in one continuous strip but may be made in several pieces and the ends made to overlap.

Should the outer cover be cut orburst, even to such an extent as to expose the circumferentially inextensible band on the tube below, no damage will accrue to the inner tube, so long as the tube cover does not come into contact with the road surface, as the laterally wound threads constitutingthe pocket prevent the tube from forcing itself through into any aperture in the outer cover. The circumferential threads in thetread distribute the strains to which the covers are subject in use, both the circumferential strains due to the drive of the engine and the action of the brake, and the lateral strains due to the swaying of the vehicle, so that the'severity of their action on the fabric is greatly reduced. They also; keep the tread of the tire true both laterallyv and radially whatever may happen to the cover, and are absolute preventative of creeping, for, since the cover isfully distended by the two tubes, and thebeads being firmly held in the channels of the rim is by the action ofthe secondary tube, no such motion is possible. i

I claim v The combination, with a wheel rim, and atire cover engaging therewith; of a pneumatic tire arranged in the upper part'of the; tire cover with its lower part extending crosswise between the sides of the cover and adapted to form a diaphragm across the cover, and a packing comprising a pneumatic tube provided with a cover of inelastic material having a reinforcing band at it's periphery, said section of substantially t"angular outline, arranged between the said tire and rim with two of its sides bearing agairi'stthe end portions of the tire cover and operating to reinforce the said diaphragm.

In testimony whereof I ture, in presence of two witnesses.

THOMA? DUNN.

v Witnesses: p i

H. D. JAMESON, S. E. Bounce,

ackixi having a cross- 

